A variety of therapeutic devices have been developed that suspend a user to support a selected portion of his weight while standing or exercising. These devices allow a user to develop strength and coordination at an earlier stage of recovery while minimizing the risk of further injury. Conventional therapeutic unloading devices include a stationary or mobile frame and a single overhanging boom arm from which the user is suspended. Typically, the boom arm is pivotally connected to the frame and supported by a suspension mechanism, such as a pneumatic or hydraulic cylinder prop, which actively or passively unloads and supports a selected portion of the user's weight.
Because the users are suspended from a single boom arm, conventional unloading devices are limited to unloading and supporting only the vertical forces exerted on the user while standing or exercising, i.e., the user's weight. When a human walks or runs (ambulation), lateral forces as well as vertical forces are generated due to the weight shifts between each leg. In many instances, an injured person has an irregular, erratic and pronounced gate, which compounds the lateral forces exerted on his body. Conventional unloading devices have not adequately compensated for the natural lateral forces exerted on a user during ambulation. Because the lateral forces are not dampened or reduced by the unloading device, the suspended user counter acts the lateral forces using his own strength and coordination. Ideally, an unloading device should reduce a selected portion of the lateral forces exerted on a suspended user as well as unloading and supporting a selected portion of the user's weight.